Pump mechanism for vacuum suspension system

ABSTRACT

A vacuum suspension system includes a pump mechanism operatively connectable to a prosthetic socket. The pump mechanism has a first member and a second member. First and second fluid chambers are located between the first and second members. The second fluid chamber is fluidly separate from the first fluid chamber, and arranged for fluid communication with the socket. An increase in volume of the first fluid chamber mechanically expands the second fluid chamber, which, in turn, creates a vacuum pressure in the second fluid chamber.

TECHNICAL FIELD

The disclosure relates to a pump mechanism for increasing vacuum in avacuum assisted suspension system.

BACKGROUND

Amputees commonly use prosthetic devices to improve their mobility andassociated quality of life. Various types of prostheses exist forreplacing the functionality of a missing limb. Transtibial andtransfemoral prostheses are effective at helping amputees regain theability to walk on their own. Various forces cause separation between aprosthetic limb and a residual limb, especially during use. This mayhappen, for example, during the swing phase of ambulation, when aprosthetic leg is subjected to both gravitational and centrifugalforces. The manner in which an artificial limb is attached to a residuallimb determines the control an amputee has over the prosthesis.

Amputees can secure prosthetic devices on their residual limbs by usingvarious vacuum or suction arrangements, whereby the maximum strength ofthe force holding the prosthesis to the residual limb is a function ofthe atmospheric pressure. The differential air pressure is routinelyreferred to as suction or vacuum by those having skill in the art. Tomaintain the sub-atmospheric pressure created within the distal end ofthe socket, sealing sleeves or liners have been provided to prevent aninflux of air around the distal end of the residual limb. Such linersare provided between the residual limb and the socket to provide forslight compression, and a gripping connection is provided to assist withthe suction suspension.

The liner can be rolled onto the residual limb so the liner-covered limbcan then be inserted into the socket. The use of conventional linersalone only provides a partial suction fit since they do not form a trueair-tight seal with the socket. Some air will slowly enter the socket,especially during the swing phase of the patient's gait and duringperiods of inactivity.

Conventional vacuum systems have been used to increase the suctionwithin the socket. Such vacuum systems may utilize a valve at a distalend of an otherwise closed socket arranged to receive the distal endportion of a residual limb. These systems work by exhausting air onlyfrom the space between the distal end of the residual limb and thedistal end of the socket interior as the limb is fully inserted into thesocket. Any air that has migrated to areas other than the distal end canremain trapped, and this action affects the optimal pressuredifferential and diminishes the strength of the suction connection.There is a clear need to provide a way to allow a user to expel air fromwithin any area of the socket.

The use of a valve is intended to allow air to be expelled from thesocket in order to maintain at least a slight negative pressure forcreating suction against the residual limb. Although the swing phase ofthe gait cycle will tend to pull the socket off the limb, walking andother weight-bearing activities may push the limb further into thesocket. Pushing the limb further into the socket causes the valve toexpel air. Conversely, directly pulling the limb out of the socket isprohibited due to the effect of suction.

Using a valve alone may not be an effective or efficient way to expelexcess air from within the socket. Many conventional vacuum suspensionsystems consequently include a vacuum pump to create the desired vacuumeffect.

Current vacuum pumps used with prosthetic sockets have severaldisadvantages, including their size, weight and difficulty of use. Formany patients, the time-consuming steps involved with operating the pumpcombined with the cumbersome placement and unreliability of accuratelyregulating pressure convinces them to avoid using prostheses entirely.

It can be seen from the foregoing there are many needs for improving onthe drawbacks of conventional vacuum suspension systems for attaching toprosthetic sockets. The embodiments of the present disclosure addressthese aforementioned shortcomings of known prosthetic systems.

SUMMARY

According to various embodiments of the disclosure, a pump mechanism isprovided for imparting a quick, easy and reliable way to regulate airdifferential within a prosthetic socket for adjusting the level ofsuction. The embodiments of the present disclosure can allow a patientto adjust the desired level of suction suspension on the fly, duringuse, or when immobile, such as when initially donning a prosthesis.

In an embodiment, a vacuum suspension system includes a pump mechanismoperatively connectable to a prosthetic socket. The pump mechanism has afirst member and a second member. First and second fluid chambers arelocated between the first and second members. The second fluid chamberis fluidly separate from the first fluid chamber, and arranged for fluidcommunication with the socket. An increase in volume of the first fluidchamber mechanically expands the second fluid chamber, which, in turn,creates a vacuum pressure in the second fluid chamber. The resultingvacuum pressure can draw air out of the socket interior and into thepump mechanism.

According to an embodiment, a pressure source is arranged to selectivelyintroduce pressure into the first fluid chamber to increase the volumeof the first fluid chamber. Because the first and second fluid chambersare fluidly separate from one another, the pressure source can introducepressure derived from different sources into the first fluid chamberwithout interfering with the vacuum pressure generated by the pumpmechanism in the second fluid chamber. This advantageously provides agreater degree of freedom of how to activate the pump mechanism. Forinstance, the pump mechanism can be controlled using pneumonic and/orhydraulic pressure from the pressure source.

Further, because the pump mechanism is operable independent of thepressure level inside of the socket, the pump mechanism can also beplaced at virtually any position and is not restricted to a particularlocation relative to the socket. For instance, the pump mechanism can belocated directly on the foot, at the knee, on the socket, or at anyother suitable location, avoiding the cumbersome placement of vacuumpumps in the prior art.

Additional features and advantages of embodiments of the presentdisclosure will be set forth in the description that follows, and inpart will be obvious from the description, or may be learned by thepractice of such exemplary embodiments. These and other features willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of such exemplary embodimentsas set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent disclosure, a more particular description of the disclosure willbe rendered by reference to specific embodiments illustrated in thedrawings. It is appreciated that these drawings depict only typicalembodiments of the disclosure and are not to be considered limiting ofscope, and are not necessarily drawn to scale. The disclosure will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings.

FIG. 1 is a perspective view of a vacuum suspension system secured to aprosthetic socket according to an embodiment of the disclosure.

FIG. 2 is an elevational view illustrating individual components of thesystem shown in FIG. 1.

FIG. 3 is a partial schematic view of the prosthetic socket of FIG. 1.

FIG. 4 is an isometric view of the embodiment of FIG. 1 including a pumpsystem.

FIG. 5 is an isometric view of a pump mechanism according to anembodiment.

FIG. 6 is a cross-sectional view of the pump mechanism of FIG. 5 in aclosed position.

FIG. 7 is a cross-sectional view of the pump mechanism of FIG. 5 in anopen position.

FIG. 8 is an exploded view of the pump mechanism of FIG. 5.

FIG. 9 is a cross-sectional view of the housing shown in FIG. 5.

FIG. 10 is an isometric view of a pump mechanism according to anotherembodiment.

FIG. 11 is a cross-sectional view of the pump mechanism of FIG. 10 in aclosed position.

FIG. 12 is a cross-sectional view of the pump mechanism of FIG. 10 is anopen position.

FIG. 13 is an isometric view of a pump mechanism according to anotherembodiment.

FIG. 14 is a cross-sectional view of the pump mechanism of FIG. 13.

DETAILED DESCRIPTION

A better understanding of different embodiments of the disclosure may behad from the following description read with the accompanying drawingsin which like reference characters refer to like elements.

While the disclosure is susceptible to various modifications andalternative constructions, certain illustrative embodiments are in thedrawings and are described below. It should be understood, however,there is no intention to limit the disclosure to the specificembodiments disclosed, but on the contrary, the intention covers allmodifications, alternative constructions, combinations, and equivalentsfalling within the spirit and scope of the disclosure.

It will be understood that, unless a term is expressly defined in thisdisclosure to possess a described meaning, there is no intent to limitthe meaning of such term, either expressly or indirectly, beyond itsplain or ordinary meaning.

The vacuum suspension system described is configured for use with aprosthetic socket, such as a lower leg prosthesis. It should beremembered, however, that the same concepts and methods described may besimilarly used for other prosthetic and/or orthopedic devices and arenot limited solely to the anatomical locations discussed. Generalanatomical terms for the human body may be used for describingparticular locations of the elements of the vacuum suspension system incomparison to the human body.

The terms “proximal” and “distal” generally refer to areas on theprosthetic socket that correspond to a location relative to where aresidual limb can be inserted. For instance, the proximal end of thesocket is its open end where a residual limb is first inserted into. Thedistal end of the socket is opposite the proximal end and includes atleast part of a cavity of the socket arranged to receive a residuallimb.

The pump and vacuum suspension system of the present disclosure isdescribed for use with a hard unitary prosthetic socket. This socketdefines a shell having a receiving portion for a residual limb and aninterior chamber for accommodating the residual limb. The shell ispreferably structurally rigid and air impervious. It should beappreciated that many configurations of the socket shell may be usedwith the vacuum suspension system.

Various embodiments of the pump may be incorporated into many prostheticappliances, including above and below the knee lower limb prosthetics,and upper limb prosthetics. While the advantages of the pump arediscussed with respect to lower limb prostheses, similar advantages canbe achieved when the pump applies to upper limb prostheses.

The prosthetic socket of the present disclosure relies on vacuumpressure to ensure a secure connection with a residual limb, while alsoimproving the fit and comfort between the socket and the limb. Thedifferential air pressure caused by using a pump creates a suctioneffect that helps retain or suspend a residual limb within a prostheticsocket.

To ensure that the suction suspension created by the pump works asintended, a liner may be worn over the residual limb so it is positionedwithin the socket. Optionally, the liner may include one or more sealelements adapted to engage at least an interior wall of the socket. Thearea below the seal component can form a vacuum zone within the socket.Besides assisting with suction inside the socket so the residual limbdoes not fall out, a liner may also be worn to provide cushioning to thelimb and to provide a gripping connection to the interior surface of thesocket. Using a liner to provide a tight fit for the residual limbwithin a socket also helps prevent air from entering the socket interiorfrom outside of the socket.

An example of a socket and method for making the same are found in U.S.Pat. No. 5,885,509, granted Mar. 23, 1999, and U.S. Pat. No. 7,105,122,granted Sep. 12, 2006, both incorporated herein by reference. Anexemplary liner sleeve for combination with the socket is found in U.S.Pat. No. 8,911,506, granted Dec. 16, 2014, U.S. Pat. No. 9,066,821,granted Jun. 30, 2015, U.S. Pat. No. 9,060,885, granted Jun. 23, 2015,U.S. Pat. No. 9,056,022, granted Jun. 16, 2015, U.S. Pat. No. 6,136,039,granted Oct. 24, 2000, U.S. Pat. No. 6,626,952, granted Sep. 30, 2003,U.S. Pat. No. 6,485,776, granted Nov. 26, 2002, U.S. Pat. No. 6,706,364,granted Mar. 16, 2004, U.S. Pat. No. 7,001,563, granted Feb. 21, 2006,and U.S. Pat. No. 7,118,602, granted Oct. 10, 2006, each of which areincorporated herein by reference in their entirety.

If the liner may not provide a true air-tight seal with the socket, someair will slowly enter the socket interior during use. The presence ofadditional air within the socket would disrupt the pressure differentialbetween the inside of the socket and the surrounding ambient air outsidethe socket, thus decreasing the suction and potentially causing the limbto become disengaged from the socket.

It is important to provide a sufficient amount of suction for suspendinga prosthesis to a residual limb during ambulation. Air may be drawn intothe interior of conventional sockets during the repeating phases of anormal gait cycle. The repetitive motions displayed between the stanceand swing phases of walking generate a pumping and pistoning effectwithin the socket, which draws in air. Even conventional prostheticsockets with sealing systems sometimes experience some air leaking intothe socket interior over a course of use.

When the pressure within the socket reaches atmospheric pressure, theincreased volume of air inside will allow the residual limb to movewithin the socket and potentially separate altogether. Any extraneousmovement of the limb within the socket could cause the patientadditional medical problems, including chafing of the skin. Moreover,patients who notice a loose connection between the residual limb and theprosthesis may also suffer increased anxiety stemming from theirinsecurity regarding whether and/or when the prosthesis will fall offtheir limb.

To combat this problem, the present disclosure provides a pump mechanismfor a vacuum suspension system that converts pneumatic or hydraulicpressure into vacuum pressure to expel air from a sealed region betweenthe socket interior and the liner-sheathed residual limb. The negativepressure within this sealed region increases as air is drawn out,correspondingly increasing the suction available to hold the prosthesisto the residual limb.

Using the pump mechanism by itself provides a desired amount of suctionwithin the socket including during ambulation or while motionless.Alternatively, it can supplement the amount of suction produced duringambulation or when the socket is initially donned.

Embodiments of the pump mechanism provide a quick, easy and reliable wayto regulate air differential within a prosthetic socket for adjustingthe level of suction. As discussed in more detail below, by providing apump mechanism that can be secured directly on the socket, a patient canadjust the desired level of suction suspension on the fly during use orwhen immobile, such as when initially donning a prosthesis.

Another advantage of the pump mechanism is that it can utilize pressure(pneumonic or hydraulic) derived from various sources such as bladderplaced on the foot or a hand pump mechanism, which allows the pumpmechanism to keep a low profile and to be located almost anywhere.

FIGS. 1-4 illustrate a vacuum suspension system 20 including a pumpmechanism 100 according to an embodiment. The vacuum suspension system20 can be operatively connected to a prosthetic socket 10 and the pumpmechanism 100 can be in fluid communication with an interior cavity 17of the socket 10.

The socket 10 is preferably rigid and can be donned over the patient'sresidual limb. A soft gel-like interface liner 30 can be placed on theresidual limb before the limb is inserted into the socket 10. The liner30 can be preferably fabricated from silicone or other impermeablematerial. Because of the gel-like qualities of the liner 30, it may needto be rolled onto the limb rather than directly pulled on like a sock.Rolling the liner 30 on the limb in this fashion can ensure that thereis only a miniscule amount of air remaining between the limb and theinner surface of the liner 30. The liner 30 is intended to provide asnug fit against the entire circumference of the limb. Providing a tightfit helps stop air from entering the space between the liner and thelimb. This type of fit is also important to prevent the liner from beingloosened or removed from the limb when tension is applied.

The liner 30 may also provide additional cushioning to the residuallimb. The liner may create an air-tight seal for trapping air within thespace between the socket interior and the exterior of the liner 30. Thiscan be accomplished by folding a proximal end 31 (shown in FIG. 1) ofthe liner 30 over the outer rim 12 of the socket 10 at its proximal end.Alternatively, the liner 30 may include one or more seal elementsadapted to engage at least an interior surface of the socket wall 11(shown in FIG. 2) to create an air-tight seal between a distal area ofthe socket interior and the exterior of the liner 30. Preferably thesocket 10 is rigid so the seal formed with the liner 30 is air tight.Partial suction may form between the liner-sheathed limb and the socket10. Maintaining such partial suction is possible if the liner isproperly contoured to the shape of the residual limb.

A total suction fit between the liner-sheathed limb and the socket 10,however, can include using the pump mechanism 100. For instance, thepump mechanism 100 can provide a vacuum for expelling excess air fromwithin the socket interior if the sealing engagement fails between theliner 30 and the socket 10. This can help reduce the likelihood of theresidual limb undesirably moving within the socket and/or potentiallyseparating altogether.

The pump mechanism 100 can be located in any suitable location but isshown attached to the socket 10. The pump mechanism 100 can be removablyattached to the socket 10 such that it can be easily removed to cleanthe socket 10 and/or the pump mechanism 100. This also allows theindividual parts of the pump mechanism 100 to be easily replaced orrepaired if they become damaged.

The pump mechanism 100 may be positioned over an aperture 14 (shown inFIG. 3) defined in the socket wall 11. The aperture 14 extends betweenan exterior surface of the socket wall 11 to the interior surface of thesocket wall 11. The interior surface defines an interior cavity 17, asthe socket 10 has a closed distal end and an open proximal end.

Optionally, a fluid regulator or valve 40 can be situated within theaperture 14 to control fluid flow between the interior and the exteriorof the socket 10. The valve 40 may be arranged to regulate the airpressure within the socket 10 so an undesirable pressure differentialdoes not adversely affect donning and doffing. The valve can also helpmaintain a sufficient amount of suction suspension for the prosthesisand regulates the air pressure in the socket 10. The valve can relievebuildup of pressure when the liner-sheathed residual limb is insertedinto the socket 10. This aids in preventing a positive internal pressurerelative to the ambient air outside of the socket 10 to allow fordonning.

The valve 40 preferably may be a one-way valve, also referred to as acheck valve. The one-way valve only allows air to be expelled from thesocket for maintaining an internal negative air pressure relative to theambient air pressure outside the socket assisting in sustaining suction.In other embodiments, the valve 40 may be omitted. For instance, thepump mechanism 100 can be directly attached to the aperture 14 and/or influid communication with the aperture 14 via a fluid conduit such as atube or hose.

In order to easily and quickly create sufficient suction suspension, thepump mechanism 100 allows a user to remove any extra air inside of thesocket 10. Creating a stronger suction suspension is useful to expeladditional air out from the socket 10 before the user even takes a firststep or during use. By activating the pump mechanism 100 to expel airfrom the socket interior, the vacuum suspension system 20 offers anamputee superior control over the level of suction suspension desired.

As discussed in more detail below, the pump mechanism 100 defines afirst fluid chamber having a variable volume and a second fluid chamberhaving a variable volume. The first fluid chamber and the second fluidchamber are separate structures that are fluidly separate from oneanother such that fluid does not flow between the two fluid chambers.

An activating positive pressure introduced into the first fluid chambercan mechanically expand the second fluid chamber, which, in turn,creates a vacuum pressure in the second fluid chamber. The resultingvacuum pressure can draw air out of the socket interior through aone-way valve in fluid connection with the second fluid chamber and thesocket interior. Because the first and second fluid chambers are influid isolation from one another, the pump mechanism can utilizepressure derived from different sources in the first fluid chamberwithout interfering with the vacuum pressure generated in the secondfluid chamber. This advantageously provides a greater degree of freedomof how to activate the pump. For instance, the pump mechanism 100 can becontrolled with pneumonic and/or hydraulic pressure.

The pump mechanism 100 can also be placed at any position and is notrestricted to a particular location. The pump mechanism 100 can belocated directly on the foot, at the knee, on the socket, or at anyother suitable location, avoiding the cumbersome placement of vacuumpumps in the prior art.

FIG. 4 shows the pump mechanism 100 operatively connected to a pumpsystem 50. A first connecting portion 52 is located on the pumpmechanism 100 to provide fluid engagement between the first fluidchamber of the pump mechanism 100 and a tubular fluid conduit 54. Thefluid conduit 54 can be attached at one end to the first connectingportion 52, and at its opposite end to a second connection portion 56for providing fluid engagement to a pressure source or an actuation pump58. The actuation pump 58 is shown disposed under the heel of a soundleg but can be placed in a suitable location. For instance, theactuation pump 58 can be located at flexible or moving junctions on theprosthetic side (e.g., between foot plates, within ankle or kneecomponents, or under a prosthetic foot), or within reach of the hand formanual pumping. In other embodiments, the actuation pump 58 may comprisea distal bladder in the socket. The actuation pump 58 can be compresseddue to the positive pressure created on it by rocking motion between thebladder and the socket. The actuation pump 58 may be configured to fitin the insole of a shoe, within a foot cover, or in a specially designedpump chamber.

The actuation pump 58 can serve as a manual pump, such that whencompressed, activating fluid (e.g., air, water and/or alcohol) insidethe actuation pump 58 is expelled through the fluid conduit 54 and intothe first fluid chamber of the pump mechanism 100. This action causesthe first fluid chamber to mechanically expand, which, in turn, causes aconcurrent expansion of the second fluid chamber of the pump.

The increase in volume of the second fluid chamber creates a vacuumeffect, which can draw air out of the socket interior through a one-wayvalve described below in fluid connection with the second fluid chamberand the socket interior. If the system 20 includes a separate valvesituated between the pump mechanism 100 and the socket 10 (e.g., thevalve 40 on the socket 10), the negative pressure created within thesecond fluid chamber can release the valve to draw fluid or air out fromwithin the socket interior. If the system 20 does not include a separatevalve between the pump mechanism 100 and the socket 10, the negativepressure within the second fluid chamber can draw air directly out fromthe socket interior via the opening in the socket wall.

When the actuation pump 58 is disengaged, the volume of the actuationpump 58 increases, which, in turn, draws the activating fluid out of thefirst fluid chamber of the pump mechanism 100 and back into theactuation pump 58, which, in turn, causes the volume of the first fluidchamber to move back towards its initial pre-inflated state. As thefirst fluid chamber returns to its initial pre-inflated state, thesecond fluid chamber of the pump mechanism 100 concurrently decreases involume and the air drawn out from the socket interior into the secondfluid chamber is expelled into the atmosphere or another space throughanother one-way valve.

The actuation pump 58 may also be activated automatically duringambulation. For instance, the actuation pump 58 can be placed underneaththe patient's prosthetic foot and/or sound foot so that when pressure isnaturally applied to the actuation pump 58 by the patient's weight whilewalking, the vacuum pumping process occurs.

For instance, the actuation pump 58 may be compressed due to thepositive pressure created on it during the heel strike stage of walking,causing the fluid to be transported through the conduit into the firstfluid chamber. This would advantageously allow a user to repeatedly pumpany excess air out of the socket interior while walking for continuoussuction suspension. The actuation pump may be compressed due to thepositive pressure created on it during stance.

While the vacuum suspension system is shown including the actuation pump58, it will be appreciated that in other embodiments the vacuumsuspension system 20 can include any mechanism suitable to compress thefluid (e.g., air, water, alcohol) into the first fluid chamber of thepump mechanism 100.

The operation of the actuation pump 58 does not have to depend on thepressure inside of the socket 10, thus the actuation pump 58 can beseparate from the pump mechanism 100 and/or the socket 10. Thisadvantageously allows the pump mechanism 100 to be more comfortable,smaller, and lighter in weight than the vacuum pumps in the prior art.For instance, placing the pump mechanism 100 directly on the socket 10does not make wearing the socket uncomfortable for the user. Securingthe pump mechanism 100 directly to the socket also decreases thelikelihood that a patient might lose the pump during use.

FIGS. 5-9 illustrate a pump mechanism 200 according to an embodiment.The pump mechanism 200 can include a second member 202 or a base, afirst member 204 or housing, and a bladder 218 situated between the base202 and the housing 204.

Referring now to FIGS. 5-7, the bladder 218 defines a first fluidchamber 217 having a variable volume and is shown to have a generallytorus or donut-like shape but may take any form. A connecting portion219 may be integrally formed on the bladder 218. The connecting portion219 can provide fluid engagement between the first fluid chamber 217 andan actuation pump or another pressure source, a tubular fluid conduit,and/or a fitting. For instance, a fluid conduit can be attached at oneend to the connecting portion 219, and can be attached at its oppositeend to the actuation pump.

Inside the pump mechanism 200 is a membrane 216 having a flexibleconfiguration that is operatively connected between the base 202 and thehousing 204. The membrane 216 can be situated at least in part within acavity 208 defined in the bottom of the housing 204. A second fluidchamber 220 has a variable volume defined between the housing 204 andthe membrane 216.

The pump mechanism 200 can be movable between a closed position as shownin FIG. 6 and an open position shown in FIG. 7. The pump mechanism 200may optionally have a resilient member 206 situated thereon whichassists in biasing the pump mechanism 200 toward the closed position.

During use, a pressure source (e.g., a pressure activated pump, amechanical pump, or an electric pump) can move the pump mechanism 200from the closed position to the open position. The pressure source(e.g., the actuation pump 58 shown in FIG. 4) can compress and forcefluid such as air, water, gel, alcohol, or another suitable fluid intothe first fluid chamber 217 defined by the bladder 218. This action cancause the volume of the first fluid chamber 217 to increase, which, inturn, causes the base 202 and the housing 204 to mechanically separate.In an embodiment, when the buildup of pressure inside of the first fluidchamber 217 exceeds the biasing force of the resilient member 206, thepressure can expand the bladder 218 so that the base 202 and the housing204 mechanically separate, activating the pump mechanism 200.

The separation of the base 202 and the housing 204 causes a portion ofthe membrane 216 to separate or pull away from the housing 204 andincrease the volume of the second fluid chamber 220 defined by the spacecreated between the membrane 216 and an interior surface of the housing204 within the cavity 208. The volume increase in the second fluidchamber 220 creates a vacuum effect, which can draw air out of theinterior cavity of a socket through an inlet valve assembly 222 in fluidconnection with the second fluid chamber 220 and the interior cavity.When the pressure source is disengaged, the pump mechanism 200 canreturn to the closed position. The bladder 218 can naturally orelastically return to its pre-inflated state such that fluid in thefirst fluid chamber 217 is returned to the pressure source from thefirst fluid chamber 217. Optionally, the biasing force of the resilientmember 206 can at least in part return the bladder 218 to itspre-inflated or a zero or near zero volume.

As the bladder 218 returns to its initial pre-inflated state, the base202 and the housing 204 move back together, this, in turn, decreases thevolume of the second fluid chamber 220. As the volume of the secondfluid chamber 220 decreases, the air of fluid drawn out from the socketinterior into the second fluid chamber 220 can be expelled to atmosphereor another space through an outlet valve assembly 224 in fluidconnection with the second fluid chamber 220. In the closed position,the first fluid chamber 217 and/or the second fluid chamber 220 can havea zero or near zero volume.

The pump mechanism 200 advantageously offers an amputee superior controlover the level of suction desired because air can be drawn out of thesocket interior whenever an activating pressure is introduced into thefirst fluid chamber 217 of the pump mechanism, consequently increasingthe vacuum within the socket 10. Further, the first and second fluidchambers are fluidly separate from one another such that fluid does notflow between the first and second fluid chambers. This advantageouslyhelps to reduce air resistance in the fluid chamber in fluid connectionwith the socket interior and allows for a variety of ways to generate avacuum at the socket-liner interface. For instance, the first fluidchamber 217 of the pump mechanism 200 can be arranged such that thepressure mechanism inside of the first fluid chamber 217 (e.g., water)is different than the pressure mechanism inside of the second fluidchamber 220 (e.g., air).

The pump mechanism 200 can also automatically return to the closedposition when the activating pressure is disengaged, leaving the pumpmechanism 200 ready for another vacuum pumping cycle.

The construction of the pump mechanism 200 will now be discussed ingreater detail in association with FIGS. 8 and 9. The housing 204 caninclude an upper section adapted to provide a support surface for theresilient member 206 and a lower section adapted to extend through ahole formed in the resilient member 206. The lower section can besmaller than the upper section. While the housing 204 is shown to have agenerally cylindrical configuration, the housing 204 may take any formincluding any polygonal prism. A variety of suitable material, includingdifferent metals, plastics and/or resins, may produce the housing 204.

The housing 204 and the base 202 can include one or more lockingfeatures 250 (best shown in FIG. 8) and the resilient member 206 caninclude corresponding detents or catches 252 (best shown in FIG. 6). Thelocking features 250 can engage the detents 252 of the resilient member206 when the resilient member 206 is loaded on the pump mechanism 100 sothat the resilient member 206 secures over the housing 204 and the base202 is at least in part locked thereon.

The cavity 208 of the housing 204 can include an undercut annular groove238 and a conical portion 240 tapering from the annular groove 238toward the bottom of the housing 204. The housing 204 can define firstport 210 and second port 212, with both the first port 210 and thesecond port 220 extending axially between an exterior surface of thehousing 204 and the second fluid chamber 220. The first and second ports210, 212 can include a counter-bore section in which the inlet valveassembly 222 and the outlet valve assembly 224 can be respectivelysituated.

The inlet valve assembly 222 can include an inlet valve 242 to controlfluid flow between the socket interior and the second fluid chamber 220.The outlet valve assembly 224 can include an outlet valve 244 to controlfluid flow between the second fluid chamber 220 and the atmosphere oranother space. The inlet valve 242 and/or outlet valve 244 may comprisea one-way valve, also referred to as a check valve. A preferred type ofone-way valve used with the pump mechanism 200 is a duckbill valve. Itshould be appreciated, however, that other types of one-way valves arepossible. The inlet valve 242 can be adapted to only allow fluid or airto be expelled from the socket and into the second fluid chamber 220 formaintaining an internal negative air pressure relative to the ambientair pressure outside of the socket. The inlet valve 242 can preventfluid in the second fluid chamber 220 from returning to the socket. Theoutlet valve 244 can be adapted to only allow air be released from thesecond fluid chamber 220 and into the atmosphere or another space. Thisadvantageously allows the vacuum pressure to be maintained throughunidirectional flow of the air through the second fluid chamber 220.

The inlet valve assembly 222 can include a male fitting 246 forconnecting the inlet valve assembly 222 to a hose, another fitting,and/or the aperture 14 (shown in FIG. 3) in the socket wall. The outletvalve assembly 224 can include a female fitting 248 for connecting theoutlet valve assembly 224 to a tube or expelling air into the atmosphereor another space from the second fluid chamber 220. It will beappreciated that the fittings may exhibit any suitable configurationand/or may be omitted.

The inlet valve assembly 222 can be in fluid communication with thesocket interior directly through the aperture 14 (shown in FIG. 14) inthe socket wall. The inlet valve assembly 222 can be in fluidcommunication with the socket interior via a tubular fluid conduit(e.g., the fluid conduit 54). For example, the fluid conduit can beattached at one end to the inlet valve assembly 222 and at its oppositeend to the valve 40. This can allow pressure to be isolated in the fluidconduit between the pump mechanism 200 and the socket interior. When thepump mechanism 200 is in fluid communication with the socket interiorvia a fluid conduit, the pump mechanism 200 can be located anywhereincluding directly on the foot or at the knee (e.g., in trans-fibularamputees).

The base 202 can be located below or generally opposite the housing 204.The base 202 can have a disc-like configuration including a hollowgenerally cylindrical stem 226 adapted for receiving a fastener 228 tofasten the base 202 to the membrane 216. Similar to the housing 204, avariety of suitable materials may produce the base 202. Further, whilethe base 202 is shown to have a disc-like shape, the base 202 may haveany form. The housing 204 and the base 202 in this embodiment are shownto be formed as two pieces. However, the housing 204 and the base 202can be formed of a single continuous member or as any suitable number ofpieces.

The stem 226 of the base 202 can be sized and configured to extendthrough a central opening defined by the bladder 218. The connectingportion 219 of the bladder 218 can extend through an aperture in thebase 202. Such an arrangement can help maintain the position of thebladder 218 between the base 202 and the housing 204 as the bladder 218expands and deflates.

The membrane 216 can exhibit any suitable shape. The membrane 216 cancomprise an elastomeric material, a synthetic rubber, a fluoropolymerelastomer, combinations thereof, and/or other suitable material. Themembrane 216 can include a body 236 arranged to be seated in the conicalportion 240 of the cavity 208 and an outer edge portion 234 arranged tobe received in the annular groove 238 of the cavity 208.

An insert 232 can be disposed within the membrane 216 that is configuredto threadedly engage with the fastener 228 extending through the stem226 of the base 202. When the base 202 and the housing 204 separate, theinsert 232 can allow the bottom of the membrane 216 to be generallyfixed relative to the base 202 while top of the membrane 216 can use atleast in part its elastic material properties and its shape to deform,bend, and/or flex inside of the cavity 208 to vary and/or form thesecond fluid chamber 220.

The engagement between the membrane 216 and the housing 204 inside ofthe cavity 208 can form a seal to inhibit fluid communication betweenthe second fluid chamber 220 and the area outside of the second fluidchamber 220. As the base 202 and the housing 204 separate, the conicalbody 236 of the membrane 216 can wedge itself in the conical portion 240of the cavity 208. This can advantageously improve the seal of thesecond fluid chamber 220 to help maintain a vacuum pressure in thesecond fluid chamber 220 as desired. The second fluid chamber 220 mayhave a variety of shapes depending at least in part on the shape of thecavity 208.

The resilient member 206 can comprise a generally u-shaped member. Theresilient member 206 can be selected based on one or more properties(e.g., stiffness) to achieve a desired biasing force on the pumpmechanism 200. While the resilient member 206 is described as agenerally u-shaped member, it will be appreciated that the resilientmember 206 can comprise any suitable member, such as, for example, atorsion spring, a torsion bar, or any other suitable member.

FIGS. 10-12 illustrate a pump mechanism 300 according to anotherembodiment. As seen, the pump mechanism 300 includes an inlet valveassembly 322 and an outlet valve assembly 324 extending radially throughports defined by a first member or housing 304. A second member or base302 can be pivotally connected to the housing 304 via a retaining pin360 extending through retaining pin holes in the housing 304 and thebase 302. The base 302 can be fixedly attached to the retaining pin 360such that the base 302 and the retaining pin 360 rotate together.Alternatively, the base 302 can be rotatably attached to the retainingpin 360 such that the base 302 rotates relative to the retaining pin360. The retaining pin 360 can be integral to the base 302 or theretaining pin 360 can be separate from the base 302.

The base 302 is rotatable about an axis extending through the retainingpin 360 to move the pump mechanism 300 between a closed position shownin FIG. 11 and an open position shown in FIG. 12. In the open position,the base 302 is rotated away from the housing 304, thus allowing air tobe drawn out of the socket interior and into a second fluid chamber 320defined by the space created between the membrane 316 and the interiorsurface of the receiving cavity 308. Similar to the pump mechanism 200,an activating positive pressure introduced into a bladder 318 can movethe pump mechanism 300 from the closed position to the open position.

The base 302 can be biased toward the closed position by a torsionspring 362 loaded on the retaining pin 360. A portion 364 of the torsionspring 362 can engage the top surface of the housing 304 to at least inpart transfer stored mechanical energy from the torsion spring 362 tothe base 302 and/or the housing 304. The stored mechanical energy in thetorsion spring 362 can force the base 302 to the closed position. In theclosed position, the second fluid chamber 320 can have a zero or nearzero volume.

FIGS. 13 and 14 illustrate a pump mechanism 400 according to anotherembodiment. The pump mechanism 400 includes a first structure 402comprising a first member or bottom plate 404, a second member or topplate 406, and a flexible seal 408 extending around the perimeter andconnecting the plates 404, 406 together. A first fluid chamber 417 isdefined between the bottom and top plates 404, 406. The plates 404, 406can be flexible and can comprise thin metal, thin plastic, thin resin,or any other suitable material. The seal 408 can comprise rubber, glue,or any other suitable material. The first structure 402 can include avalve assembly 416 adapted to control fluid flow between the first fluidchamber 417 and a pump or other pressure source.

Inside of the first structure 402 is a second structure 410 connected tothe top plate 406 and the bottom plate 404. The second structure 410 cancomprise a clam-type structure including a pair of elastomeric disksfacing each other. Each disk can have a suction cup-like shape. Thesecond structure 410 can define a second fluid chamber 420 formedbetween the elastomeric disks. The second structure 410 can include aninlet valve assembly 422 received in a first port and an outlet valveassembly 424 received in a second port that are independent from thevalve assembly 416 incorporated in the first structure 402. The inletvalve assembly 422 can be adapted to control fluid flow between thesocket interior and the second fluid chamber 420 and the outlet valveassembly 424 can be adapted to control fluid flow between the secondfluid chamber 420 and the atmosphere or another space. The inlet valveassembly 422 and the outlet valve assembly 424 may include a one-wayvalve or check valve 442, 444, respectively, to maintain unidirectionalair flow through the second fluid chamber 420.

It will be appreciated that the embodiments of the pump mechanism are tobe regarded as exemplary only. For example, while the membrane is showncomprising a disc-like member, in other embodiments, the membrane maycomprise a Belleville washer, a membrane having a flexible and rigidsection, a diaphragm valve, or any other suitable sealing element. Whileembodiments of the pump mechanism are described in use with the vacuumsuspension system 20, other vacuum suspension systems are possible. Someexample vacuum suspension systems are found in U.S. patent applicationSer. No. 13/766,086, filed on Feb. 13, 2013, and Ser. No. 14/192,949,filed on Feb. 28, 2014, both incorporated herein by reference. In otherembodiments, the pump mechanism can include three, four, or any othersuitable number of fluid chambers.

It should also be appreciated that many variations of the bladder havingdifferent shapes and/or sizes can be used for separating the first andsecond members. Although such variations may differ in form, theyperform substantially similar functions. In other embodiments, the inletvalve and/or the outlet valve can comprise an umbrella valve or othersuitable valve. In yet other embodiments, the force utilized to separatethe first and second members can be a mechanical or magnetic force froma linear actuator, magnets, or any other suitable source. In yet otherembodiments, the inlet valve assembly and the outlet valve assembly maycomprise a single assembly including a single valve.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments are contemplated. The various aspects andembodiments disclosed herein are for purposes of illustration and arenot intended to be limiting. Additionally, the words “including,”“having,” and variants thereof (e.g., “includes” and “has”) as usedherein, including the claims, shall be open-ended and have the samemeaning as the word “comprising” and variants thereof (e.g., “comprise”and “comprises”).

The invention claimed is:
 1. A vacuum suspension system comprising: apump mechanism including: a first member; a second member; a bladderdisposed between the first and second members and defining a first fluidchamber located between the first and second members; a second fluidchamber located between the first and second members, the second fluidchamber fluidly separate from the first fluid chamber, wherein anincrease in volume of the first fluid chamber mechanically expands thesecond fluid chamber to create a vacuum pressure in the second fluidchamber; and a pressure source fluidly connected to the bladder andseparate from the pump mechanism, the pressure source arranged toselectively compress and force fluid into the first fluid chamber toincrease the volume of the first fluid chamber.
 2. The system of claim1, wherein the volume increase in the first fluid chamber mechanicallyseparates the first and second members of the pump mechanism to createthe vacuum pressure in the second fluid chamber.
 3. The system of claim1, further comprising a membrane having an outer edge portion secured tothe first member of the pump mechanism, the second fluid chamber havinga volume defined between the first member of the pump mechanism and themembrane.
 4. The system of claim 3, wherein the membrane deforms to varythe volume of the second fluid chamber.
 5. The system of claim 3,wherein the increase of volume in the first fluid chamber pulls thefirst member of the pump mechanism and a portion of the membrane apartto increase the volume of the second fluid chamber.
 6. The system ofclaim 3, wherein the first member of the pump mechanism comprises ahousing defining first and second ports, the second fluid chamber beingin fluid communication with the first and second ports.
 7. The system ofclaim 6, further comprising a connector attached to a portion of themembrane opposite the first member of the pump mechanism.
 8. The systemof claim 7, wherein the second member of the pump mechanism comprises abase member situated under the housing and connected to the connector.9. The system of claim 8, further comprising a bladder situated betweenthe housing and the base member, the bladder having a torusconfiguration defining a center opening, the connector extending throughthe center opening of the bladder.
 10. The system of claim 1, furthercomprising a resilient member engaging at least one of the first andsecond members of the pump mechanism, and arranged to bias the secondfluid chamber toward a zero or near zero volume.
 11. The system of claim10, wherein the resilient member is arranged to bias the first fluidchamber toward a zero or near zero volume.
 12. A prosthetic systemcomprising: a pump mechanism operatively connectable to a prostheticfoot, the pump mechanism including: a housing defining first and secondports; a membrane having an outer edge portion secured to the housing; abase member disposed below the membrane; a bladder disposed between thehousing and the base member; a first fluid chamber with a volume definedby the bladder; a second fluid chamber with a volume defined between thehousing and a first side of the membrane, the second fluid chamberfluidly separate from the first fluid chamber and in fluid communicationwith the first and second ports, wherein an increase in volume of thefirst fluid chamber mechanically expands the second fluid chamber tocreate a vacuum pressure in the second fluid chamber.
 13. The system ofclaim 12, further comprising a connector attached to a second side ofthe membrane opposite the first side of the membrane, the connectorconnecting the membrane to the base member.
 14. A vacuum suspensionsystem comprising: a pump mechanism including: a first member; a secondmember; a bladder disposed between the first and second members anddefining a first fluid chamber located between the first and secondmembers; a second fluid chamber located between the first and secondmembers, the second fluid chamber fluidly separate from the first fluidchamber, wherein an increase in volume of the first fluid chambermechanically expands the second fluid chamber to create a vacuumpressure in the second fluid chamber; and a pressure source fluidlyconnected to the bladder and separate from the pump mechanism, thepressure source arranged to selectively compress and force fluid intothe first fluid chamber to increase the volume of the first fluidchamber, wherein the volume increase in the first fluid chambermechanically separates the first and second members of the pumpmechanism to create the vacuum pressure in the second fluid chamber. 15.A vacuum suspension system comprising: a pump mechanism including: ahousing defining first and second ports; a base member situated underthe housing; a membrane having an outer edge portion secured to thehousing; a connector attached to a portion of the membrane opposite thehousing; a bladder situated between the housing and the base member, thebladder having a torus configuration defining a center opening, theconnector extending through the center opening of the bladder; a firstfluid chamber located between the housing and the base member; a secondfluid chamber having a volume defined between the housing and themembrane, the second fluid chamber fluidly separate from the first fluidchamber and in fluid communication with the first and second ports,wherein an increase in volume of the first fluid chamber mechanicallyexpands the second fluid chamber to create a vacuum pressure in thesecond fluid chamber.